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    <script>
      var numDistinct = function (s, t) {
        let dp = new Array(s.length + 1).fill().map(() => new Array(t.length + 1).fill(0))
        for (let i = 0; i <= s.length; i++) {
          dp[i][0] = 1
        }
        for (let i = 1; i <= s.length; i++) {
          for (let j = 1; j <= t.length; j++) {
            if (s[i - 1] != t[j - 1]) {
              dp[i][j] = dp[i - 1][j]
            } else {
              dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j]
            }
          }
        }
        return dp[s.length][t.length]
      }
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